The acoustic design or layout of enclosed partial cabins within cabin or freight compartment often has to satisfy especially high noise protection requirements for the purpose of the relaxation/sleep of the aircraft crew or passengers. In that regard, the installation location of the partial cabins is frequently fixed or specified in surrounding environments with especially high background or environmental noise levels. Therefore, in the acoustic design of the partial cabin, it depends on taking into account the background or environmental noise about the partial cabin and the noise transmission paths.
It is known to install the partial cabin in an original fuselage section, and to produce a diffuse noise field as an acoustic re-creation of engine jet noise and boundary layer noise outside of the section with the aid of reverberation chambers mounted or built onto the fuselage contour. Thereby, the fuselage section is excited to undergo vibrations, which, on its part, radiates noise in the form of airborne noise and also structure-borne noise inwardly toward the inside and thus also in the direction of the partial cabin, and thereby acoustically excites the partial cabin.
In that regard, the fuselage section divides the externally applied noise excitation with correct proportions into inwardly directed airborne and structure-borne noise. The structure-borne noise coupling into the partial cabin runs into the fuselage segment with correct intensity and phase due to the original partial cabin installation. Thereby, noise level measurements in the partial cabin are representative, and modifications of the partial cabin for the purpose of noise reduction measures can be designed and tested or measured.
However, this process or manner of proceeding always requires the availability of an original fuselage section, which leads to high costs especially in connection with high capacity aircraft.